U.S. Pat. No. 4,358,455 discloses heterocyclic aminoethanol compounds which are useful as cardiovascular agents. The generic disclosure of that patent encompasses the six compounds of this invention, however, there is no specific disclosure of the instant six compounds. It has been discovered that the compounds of this invention have a surprisingly and unexpectedly high level of activity and safety as growth promotion agents when compared to the disclosed compounds closest in structure to the instant six compounds. In addition, U.S. 4,761,421 discloses the use of one compound within the scope of 4,358,455 which has growth promotion activity, however, the instant compounds have a substantially higher margin of safety than this single compound.